Head coach Aitor Karanka is also trying to tie up an initial loan move for Barragan's club-mate Alvaro Negredo as he attempts to beef up his attacking options for life in the Barclays Premier League.

Former Liverpool full-back Barragan would join Victor Valdes, Viktor Fischer, Bernardo Espinosa, Marten de Roon and Jordan McGhee as new recruits, and Karanka has further irons in the fire with deals for Borussia Dortmund defender Neven Subotic and Uruguayan midfielder Gaston Ramirez, who spent the second half of last season on loan to Boro from Southampton, in place subject to work permits.

Further additions would come as a boost to the Spaniard, who has been dealt a triple injury blow just weeks before the start of the new campaign.

Skipper Grant Leadbitter will miss the start of the season after undergoing surgery to repair a hernia problem.

The 30-year-old midfielder was a key figure in Boro's promotion drive last season despite playing through the final two months of the campaign only after having a series of painkilling injections.

Leadbitter has now had an operation, but the problem was more extensive than first thought and he will not now be fit for the start of the new season.

A statement on the club's official website, www.mfc.co.uk, said: "Grant Leadbitter is set to miss the start of the 2016/17 Premier League season after undergoing surgery earlier this year.

"The Boro skipper had an operation to correct an injury he had been carrying for the last two months of the season and further investigation has shown that the injury is worse than first anticipated."

Karanka will also be without full-back James Husband, who is due to have surgery on the shoulder he dislocated during last Saturday's 6-0 friendly victory at York on Monday.

And the bad news is that the defender could be sidelined for up to three months.

The statement continued: "James Husband also joins the injury list and is facing a lengthy spell out of action with the left-back awaiting an operation to repair a dislocated shoulder.

"Husband fell awkwardly at York City last Saturday and had to be replaced by George Friend. The defender could be out for up to three months."

Meanwhile, central defender Daniel Ayala will sit out Saturday's friendly trip to Doncaster, in which Valdes and Fischer could be handed debuts, with the ankle problem he suffered shortly after his return for pre-season training.